What kinds of wetlands are there?

    

    There are multiple ways of dividing different types of wetlands. In the US it is common to divide them into 4 categories based on hydrology, vegetation and soils:

Bogs - containing mosses and precipitation-based hydrology and peaty soil;

Fens - with grasses, groundwater and peaty soil;

Marshes - dominated by herbaceous plants and hydric soil;

And swamps - characterized by woody plants and hydric soil.

 

A map of wetland distribution in Poland. Source.

    However the main dividing factor used in Poland to classify wetlands is the mere presence of peat! The classification of Polish wetlands is then as follows:

        Peatlands are almost 30% of all wetlands in Poland and cover about 4% of the country. Their estimated area is about 1.3 millions ha (with some error margin since the ones smaller than 1 ha are not included due to the increased difficulty of counting all small wetlands). 

The National Park of the Biebrza River. Source. 

        Peatless wetlands constitute the vast majority (over 70%!) and cover about 10% of the country. An

interesting fact is that even though they are so much more common than peatlands, they are less researched. This is due to the phrase "peatless wetlands" including plenty of varying environments so determining their exact borders and areas as well as their level of degradation is challenging.

Floodplains of the Narwia river. Source.

    It is also worth adding that in Poland only 16% percent of wetlands remained in their natural or almost natural state - the rest has been dried out for agricultural use or other reasons.